Embodiments of the present invention relate generally to safety devices and systems and in particular, embodiments of the present invention relate to an air belt device including an inflatable member folded and stored in a manner to provide maximum comfort and protection to an occupant, and an air belt apparatus employing the same.
A conventional air belt apparatus is described in Japanese Patent Unexamined Publication No. H05-85301. FIG. 1 is a perspective view of an air belt apparatus according the publication.
As shown in FIG. 1, the air belt apparatus 1 includes a shoulder belt 2 diagonally extending from the right side of an occupant to the left side of the occupant, a lap belt 3 extending from the right side of the occupant to the left side of the occupant, a buckle device 4 disposed on, for example, a vehicle floor, a tongue 5 to be inserted into and engaged with the buckle device 4 when the occupant wears the shoulder belt 2, and a through-anchor 6 for guiding the shoulder belt 2.
The shoulder belt 2 includes a webbing 2a which is similar to a conventional and general seat belt and an air belt 2b connected to an end of the webbing 2a. The webbing 2a is slidably guided and hung-through by the through-anchor 6. The other end of the webbing 2a is connected to a seat belt retractor 7 with an emergency locking mechanism (ELR) which is fixed to the vehicle body. The webbing 2a is arranged in such a manner as to be wound into the seat belt retractor 7.
The upper end of the air belt 2b is connected to the webbing 2a by sewing or some other form of attachment and the lower end of the air belt 2b is connected to the tongue 5 for connection to the buckle device 4. The air belt 2b is positioned to be in contact with the occupant.
The lap belt 3 includes a normal belt which is the same as a typical conventional seat belt, of which one end is connected to the tongue 5 and the other end is connected to a seat belt retractor 8 with an emergency locking mechanism (ELR) which is fixed to the vehicle body. A gas generator 9 is connected to the buckle device 4 for generating high-pressure gas when required in an emergency situation such as a vehicle collision.
The tongue 5 and the buckle device 4 are provided with paths for introducing gas from the gas generator 9 to the air belt 2b. 
The air belt 2b includes a large-width belt-like bag (e.g., an inflatable member) which is folded into a small-width belt-shape and is covered with a cover. The air belt 2b retains its belt-shape under normal conditions. The air belt apparatus 1 is used in a manner similar to that of a general seatbelt. When the gas generator 9 is operated upon a vehicle collision, the air belt 2b is inflated, as is shown by the dashed lines in FIG. 1, so as to protect the occupant.
In the conventional air belt apparatus 1 described above, the separate webbing 2a is required to be connected to the air belt 2b and wound around the retractor 7, because the thickness of the air belt 2b is larger than that of the webbing 2a. This causes wrinkles to be formed on the contact surface with the through-anchor 6 and the air belt 2b. As a result, the air belt 2b is difficult to be passed through the through-anchor 6 and also difficult to be wound around the retractor 7. An added problem which makes the air belt 2b so difficult to pass through the through-anchor 6 and causes the air belt 2b to have a bumpy surface is the manner in which a inflatable member is folded and stored.
FIG. 2(a) is a plan view showing a portion around a joint between the webbing 2a and the air belt 2b. FIG. 2(b) is a plan view of the inflatable member, and FIGS. 2(c), (d) and (e) are sectional views taken along lines C-C, D-D, and E-E in FIG. 2(a), respectively.
As shown in FIGS. 2(a), (c), (d) and (e) the air belt 2b includes the inflatable member 100 and a knit cover 120 made of woven fabric and surrounding the inflatable member 100. The inflatable member 100 is formed in such a configuration that a portion confronting the chest and abdomen of an occupant in a seat has a larger area. The portion with larger area is folded to be in a band-like configuration as shown in FIGS. 2(b), 2(c) and 2(d).
As illustrated in FIGS. 2(c) and (d), the inflatable member 100 is folded in such a manner that the edges of the sewn portions face outward toward the knit cover 120. These outward peripheral sewn portions are unsightly as they make the air belt 2b appear bumpy and also hamper the air belt 2b from passing through the through-anchor 6. Further, the length of the overall air belt 2b is increased by having the edges of the sewn portions folded outward.
Therefore, it is desired to have an air belt device such that the smoothness to the touch of the air belt is improved, the overall length of the air belt is shortened and the air belt can pass through the through-anchor easily.